Many blood flow experiments employ hand pumping techniques for inflating occlusion cuffs. Blood flow information obtained from using hand-pumping techniques is frequently inaccurate or if accurate is hard to interpret due to a considerable range of possible variations. The need therefore exists for equipment which would automatically inflate and deflate the cuffs to preset pressures and for preset time durations. Such automatic cuff inflation devices as are known may be adequate for large size laboratories. For small laboratories or for specialized environments such as exist, for example, in space flights, it is required that such automatic devices be simple to operate, be suitable for carrying out blood flow experiments in connection with instrumentation and power supplies used in space flights, and have controls that are easily accessible to the astronaut whose blood flow is being measured. Such controls include means for selecting the cuff maximal fill pressure, the duration of maintaining this fill pressure, and the time of initiating the inflation-deflation cycle in order to optimize function for different individuals.
It is a main object of this invention to provide logic-controlled valves in an occlusive cuff system which is characterized by extremely accurate pressure-time cycles that meet all the above-mentioned desiderata and others which will become apparent from the following detailed description of the invention.